Question 1

What hashing algorithms does this tool support?

Accepted Answer

This hash generator supports five algorithms: MD5 (128-bit, 32 hex chars), SHA-1 (160-bit, 40 hex chars), SHA-256 (256-bit, 64 hex chars), SHA-384 (384-bit, 96 hex chars), and SHA-512 (512-bit, 128 hex chars). You can switch between algorithms with a single click and compare outputs side by side. SHA algorithms also support HMAC mode with a user-supplied secret key.

Question 2

What is HMAC and when should I use it?

Accepted Answer

HMAC (Hash-based Message Authentication Code) is a construction that combines a cryptographic hash function with a secret key to produce a keyed digest. Unlike a plain hash, an HMAC can only be verified by someone who knows the key. Use HMAC when you need to authenticate that a message was produced by a party with the secret key and has not been modified. Common uses: signing API requests (HMAC-SHA256 is used in AWS Signature Version 4 and Stripe webhook verification), generating JWT signatures (HS256 algorithm), and secure cookie integrity checks.

Question 3

Which hashing algorithm should I use for my project?

Accepted Answer

For most new projects, use SHA-256. It offers strong collision resistance, is supported natively in all modern browsers and runtimes, and is the default in most security standards. Use SHA-512 if you need a higher security margin or if your platform benefits from 64-bit word operations. Use SHA-384 for TLS cipher suites that require it (TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384). Avoid MD5 and SHA-1 for any security purpose; they have practical collision attacks. For password storage, use a dedicated function such as bcrypt, Argon2, or scrypt instead of any of these algorithms directly.

Question 4

Can a hash be reversed?

Accepted Answer

No. Cryptographic hash functions are one-way: given a hash output, it is computationally infeasible to find the original input. This property is called preimage resistance. You cannot reverse or decrypt a hash. The only way to find an input that matches a hash is to guess inputs and compare their hashes, which is why rainbow tables exist for common passwords and why secure password hashing uses salts to defeat precomputed lookup tables.

Hash Generator

Frequently asked questions

More JSON Tools

About Cryptographic Hashing